Cerebral cavernous malformations (CCMs) of the brain are vascular lesions, which are present in up to 0.4% of the general population and often are accompanied by seizures, migraine, hemorrhagic stroke and other neurological outcomes. These lesions can occur sporadically, or as an autosomal dominant trait. Our group has recently identified the CCM1 gene, which is responsible for the majority of all familial CCMs and principally the cause for the familial form of CCMs in the Hispanic population (Sahoo et al., 1999). With the discovery of the CCM1 gene, we have developed a significant insight into the pathology of this "familial stroke." There are two additional CCM genes that remain to be identified, CCM2 on chromosome 7p and CCM3 on chromosome 3q. We will utilize our previously successful approach for positional cloning, which employs a strong computational approach to transcript identification in order to identify positional candidates for sequencing. We believe that the resources will have accumulated and the approach we have established will allow us to identify the genes for CCM2 and CCM3. After identifying the genes responsible for CCM2 and CCM3, we will begin to investigate their role in the cell, and in particular, their role in the pathophysiology of CCM. These types of experiments include overall protein expression patterns in the embryo and the adult, cellular compartment localization studies, and a search for interacting proteins using the yeast two-hybrid screen. These data will provide the molecular/cellular framework from which to launch a more detailed analysis of these proteins in a future proposal. Our ultimate objective is to aid in understanding the fundamental mechanisms responsible for different forms of familial neurovascular disease. The availability of a model, where the primary genetic determinates have been identified unambiguously, will greatly expedite the search for the basic mechanisms involved in "familial stroke" and to a better understanding of neurovascular disease, in general.